There are numerous types of automatic controllers that typically incorporate conventional motor-driven electric clocks or solid-state electronics or both technologies combined. These systems provide for individual start times for particular irrigation cycles and watering schedules and may include calendar programs that provide the ability to select particular days and distribution periods with these control units.
Solid-state irrigation controllers have been displacing the use of electromechanical controllers, particularly in larger applications. Solid-state controllers replace the electric motors, mechanical switches, pins, cams, levers, gears, and other mechanical devices with solid-state electronic circuitry that executes a programmed response and are typically much less expensive than electromechanical systems. Many prior art solid state stand alone irrigation controllers incorporate a programmable microprocessor computer with a user interface that enables the programming of different watering stations or zones based on variables such as daily, weekly, or biweekly start times, having differing watering lengths. Other variables that add “smart” system functionality may be programmed into such systems and can include the use of field sensors that can report a variety of environmental or system component conditions or states. These can also be referred to as “smart” controllers or stand-alone controllers. Central or centrally control system controllers usually include such “smart” system functionality.
Some controllers visually communicate the current status of the system's programmable variables by use of indicators such as liquid crystal displays, analog indicators or binary messages sent to a computer and graphically represented on screen using proprietary software. Audible and visual alarms to inform the user of malfunction conditions in a control system are used as well.
In a typical solid-state irrigation system the water supply to sprinklers of each watering zone is regulated by a remote control valve (RCV) having a solenoid that includes one or more sprinklers. An RCV controls the flow of water from a pressurized water source to the sprinklers of a given watering zone. Main or master control valves (MCV's) that regulate water flow to one or more RCV's may also be provided. The MCV can function as a fail-safe device should a waterline break or malfunction occur in the main line or an RCV or its line. RCV's and MCV's are types of supplemental field electromechanical control devices. Field sensors may also be provided so that in such systems sensor inputs can be interpreted by the microprocessor and newer controllers can respond to the inputs accordingly, by shutting down an MCV at the main water feed location to prevent water waste and property damage caused by a line break.
There are two significant types of control systems in use: the stand-alone controller and the centralized-satellite or remote control central system. Generally, the stand-alone controller is operated locally by a user and functions independently of any other controller or of any network communication system, as noted in U.S. Pat. No. 5,870,302 to Oliver issued on Feb. 9, 1999. '302 shows a host computer that analyzes data which after computing variables send data from the computer to the controller. In the irrigation market, these units are made as the Sentinel by The Toro Company or Maxicom by the Rainbird Corporation, and are designed for large field applications such as golf courses or municipalities. Data can also be directly input by the user, as noted in U.S. Pat. No. 5,921,280 to Ericksen on Jul. 13, 1999, where a user provides input via a handheld unit to the controller. These systems are marketed by The Orbit Corporation as Superstar RF, by Hunter Industries as SRR and by the Rainbird Corporation as the RM series. The remote control central system in contrast networks monitoring and control functions by communicating between a plurality of stand-alone controllers and a central, user-operated computer, as shown in U.S. Pat. No. 6,600,971 issued to Smith on Jul. 29, 2003. Central remote control system technology maximizes user efficiency by giving a single individual the capability to monitor and control a number of stand-alone controller devices simultaneously and thereby allow greater optimization of program schedules and water applications. The three prior art patents show hardwired or wireless control of the controller, but uses only hardwired connections to the actual sprinkler valves. The wireless controller only interfaces with the sprinkler controller and not the actual sprinkler valve directly.
Both stand-alone and central control systems can include field sensor devices to allow the monitoring and processing of signals generated by field sensors. They can also sense electrical current load conditions on each of their MCV and RCV wire leads. These control systems can be programmed to respond in specified ways depending upon the sensor inputs detected. This style of full duplex system is used to monitor valve status (open, closed, shorted) as well as the existing controller can sense current load conditions and compare it to what is anticipated by system parameters. If the existing controller does not sense a current load after energizing a valve, then the controller will know that the valve is not operating properly. It is important to understand that full duplex entails not only two way communication but also confirmation of the actual sending and receipt of information is monitored to ensure that the system is able to communicate properly.
Most control systems open or close valves or other devices by sending an electric current over a wire at a user-defined scheduled time interval. Some control devices have numerous connection points where several solenoid or other mechanically actuated valves can be attached or other types of devices that can be switched on or off with a relay. Similarly, signals generated from field sensor inputs, such as liquid flow, atmospheric, soil moisture content and other types can be received by contemporary controllers via dedicated wire paths.
Multiple stand-alone control systems are frequently used on larger land areas or properties, where multiple stand-alone controllers must be used because of the great distances that lay between controllers and valves. The additional controller units may be required because of limitations caused by electrical line impedance, the distance wire can be run and the maximum amount of electrical impedance, or because of the remote proximity to water supply lines or meters. Though expensive, it is usually substantially cheaper to place more controllers near a water supply line than it is to move the supply line closer to a controller. These types of irrigation systems therefore often require a greater number of control units, and at a greater expense, to adequately control the supply of water to far reaching areas. Larger property sites such as those used in cities, with highways, planned communities, golf courses, institutional or commercial facilities and the like, are difficult to maintain and manage because of the shear number of control points and the remote proximity between control units.
Central control technology was developed to improve the efficiency of managing the distribution of water to large areas and to provide fault detection and reaction capability, but all carry a substantial economic cost to the purchaser of such systems. The benefit of investment is significantly realized in larger locations where a single stand-alone or central control unit can have a very positive economic impact on a large area. The opposite, however, is true when installing the same system in a smaller area. Roughly, the same dollar investment must be made to control an irrigation system on a smaller land area, but with reduced possibility of return on investment, because the smaller property will not have as great a water waste or savings potential as a larger one.
However, though waste or savings potential may or may not be diminished, liability potential may be as great or greater depending upon the areas location. For example, a broken line in a bad location can cause substantial property or other collateral damage. Furthermore, most cities or large facilities are comprised of numerous smaller areas so when combined, can amount to significant total area or acreage. Managing acreage, again, becomes an important issue relative to use efficiency and waste minimization. Therefore, singularly or a combination of these two points make incorporating “smart” or central control technology features to smaller areas more critical and important.
Where there are numerous smaller areas within a larger site, such as a city, they are usually not included when converting several stand-alone control systems to a “smart” or central control system because of the high cost of retrofitting each control unit. By today's figures, a centrally controlled stand-alone control unit that communicates wirelessly to a host computer can cost between $6,000–$12,000; where as, a smaller single basic control unit without the capabilities of a larger “smart” stand-alone wireless system can cost 75%–95% less. Cities will place the more expensive “smart” stand-alone systems in larger areas and use the less expensive and subsequently less capable single control units, without connection to host computers, in smaller areas.
The present invention will enable cities and other large system users an economical alternative and option to forego the use of the more limited single control units by incorporating the feature content of the more capable “smart” system or a centrally controlled system by providing a wireless bridge that can connect the control requirements of the smaller areas into the functionality of “smart” systems employed in near-by larger areas. Further, retrofitting an existing stand-alone or central system to incorporate an MCV and field sensing inputs, processing and control capabilities is often neglected completely and not installed due to the high cost and difficulty that can be associated with laying wire to connect the devices. In retrofit applications, it is also not uncommon to encounter adverse site conditions which require trenching great distances or through established areas to complete wire runs. Many times roads, highways, severe elevation changes, buildings, bridges or a multitude of other types of structures must be traversed to run the necessary wire to add sensors or electromechanical devices such as MCV's or RCV's.
Modern irrigation controllers and central control system technology is designed to optimize watering efficiency, to minimize water waste and optimize the irrigation system for other environmental conditions that are associated with water waste, such as soil erosion. A solution is therefore needed to reduce the economic impact of incorporating these newer technologies into otherwise cost-prohibitive or difficult to impossible installation locations.
What is needed then is a subsystem that can be retrofitted or adapted to most any commonly available control system, whether stand-alone or central controlled, and produced by any manufacturer that will provide a wireless communication link between the existing control unit, which includes the monitoring and processing controls and capability to act upon those control inputs, and the existing electromechanical devices such as MCV's, RCV's, and field sensor devices that would otherwise require a hardwired connection.
What is also needed is a subsystem that provides the existing apparatus the capability to upgrade the functionality of an existing controller system without having to replace the existing controllers or other components of the system. Adding or retrofitting certain technology features to an existing system that lacks those features may provide a cost effective alternative to total system replacement, such as adding digital sensors to an analog control system or adding analog sensors to a digital system. It is the incompatibility between devices and controllers that communicate through different signal waveforms or interface protocols, analog versus digital, along with the difference between the proprietary controllers and devices unique to different manufactures, Toro versus Rainbird versus Hunter or Orbit, that makes retrofitting older systems very expensive and complicated. Moreover the end user, whether a municipality, an institution, or a commercial, communal or other user would benefit significantly because existing equipment would not need to be eliminated or replaced, so the user would not incur the loss of an initial investment, while availing the user of newer water-saving technology features. What is also needed is a method of converting an existing hardwired controller system to wireless technology while using all existing components and circuitry of any waveform and manufacturer.